Mixing up 1066mhz ram and 1333mhz ram

This is a discussion on Mixing up 1066mhz ram and 1333mhz ram within the RAM and Power Supply Support forums, part of the Tech Support Forum category. Can i mix both 1066mhz and 1333mhz laptop rams together? Do they have any bad effects or something after i

Mixing different speeds/brands/voltages of ram is generally considered a bad idea. Sometimes the "faster" memory will get clocked down to the slower ram's speed but there is definately a high chance that the result will be unstable. With that being said, i've seen it done without problems once or twice. You probably wouldn't hurt anything physically but there isn't a definite chance that everything will run smooth and stable.

I also agree with the idea that if the motherboard runs the RAM together, the speed will be dropped to the higher matching speed available. Give it a try, and use a program like Speccy to check the RAM afterwards. I can bet they will both operate at 1066MHz.